expanding onhttps://bugs.python.org/issue36983the docs are also a bit out of date in placesI'm not sure how to document something that appeared in two versions, but I'll leave that part to review.Using data generated / collected inhttps://github.com/asottile/flake8-typing-imports via this script:https://github.com/asottile/flake8-typing-imports/blob/master/bin/build-generatedand then analyzed with this script:from flake8_typing_imports import SYMBOLSALL = set().union(*(v for _, v in SYMBOLS))for k in sorted(ALL):    state = False    for i, (v, ks) in enumerate(SYMBOLS):        if state is False and k in ks:            print(f'{k}: new in {v}')            state = True        elif state is True and k not in ks:            print(f'=> {k}: removed in {v}')            state = FalseI've found the following:$ python3 t.py | grep -v 'new in 3\.5\.0'AsyncContextManager: new in 3.5.4=> AsyncContextManager: removed in 3.6.0AsyncContextManager: new in 3.6.2AsyncGenerator: new in 3.6.1AsyncIterable: new in 3.5.2AsyncIterator: new in 3.5.2Awaitable: new in 3.5.2ChainMap: new in 3.5.4=> ChainMap: removed in 3.6.0ChainMap: new in 3.6.1ClassVar: new in 3.5.3Collection: new in 3.6.0ContextManager: new in 3.5.4Coroutine: new in 3.5.3Counter: new in 3.5.4=> Counter: removed in 3.6.0Counter: new in 3.6.1DefaultDict: new in 3.5.2Deque: new in 3.5.4=> Deque: removed in 3.6.0Deque: new in 3.6.1ForwardRef: new in 3.7.0GenericMeta: new in 3.5.4=> GenericMeta: removed in 3.6.0GenericMeta: new in 3.6.1=> GenericMeta: removed in 3.7.0NewType: new in 3.5.2NoReturn: new in 3.5.4=> NoReturn: removed in 3.6.0NoReturn: new in 3.6.2OrderedDict: new in 3.7.2TYPE_CHECKING: new in 3.5.2Text: new in 3.5.2Type: new in 3.5.2